Share ffmpeg version setups and other fixes

Signed-off-by: Dmitry Rogozhkin <dmitry.v.rogozhkin@gmail.com>

Author: Dmitry Rogozhkin

src/torchcodec/__init__.py

@@ -4,11 +4,11 @@
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
 
-import os.path as _osp
+from pathlib import Path
 
 # Note: usort wants to put Frame and FrameBatch after decoders and samplers,
 # but that results in circular import.
-from ._core import core_library_path, variant
+from ._core import core_library_path, ffmpeg_major_version
 from ._frame import AudioSamples, Frame, FrameBatch  # usort:skip # noqa
 from . import decoders, samplers  # noqa
 
@@ -18,4 +18,9 @@
 except Exception:
     pass
 
-cmake_prefix_path = _osp.join(_osp.dirname(__file__), "share", "cmake")
+# `torchcodec.cmake_prefix_path` is a Python-based way to programmatically
+# obtain the correct CMAKE_PREFIX_PATH value for the TorchCodec installation.
+# It can be used in a build system of a C++ application to ensure that CMake
+# can successfully find TorchCodec C++ libraries. This variable is exposed
+# as TorchCodec API.
+cmake_prefix_path = Path(__file__).parent / "share" / "cmake"

src/torchcodec/_core/CMakeLists.txt

@@ -245,16 +245,16 @@ if(DEFINED ENV{BUILD_AGAINST_ALL_FFMPEG_FROM_S3})
         you still need a different FFmpeg to be installed for run time!"
     )
 
-    # This will expose the ffmpeg4, ffmpeg5, ffmpeg6, ffmpeg7, and ffmpeg8 targets
+    # This will expose the torchcodec::ffmpeg{N} (N=4,5,6,7,8) targets
     include(
         ${CMAKE_CURRENT_SOURCE_DIR}/fetch_and_expose_non_gpl_ffmpeg_libs.cmake
     )
 
-    make_torchcodec_libraries(8 ffmpeg8)
-    make_torchcodec_libraries(7 ffmpeg7)
-    make_torchcodec_libraries(6 ffmpeg6)
-    make_torchcodec_libraries(4 ffmpeg4)
-    make_torchcodec_libraries(5 ffmpeg5)
+    make_torchcodec_libraries(8 torchcodec::ffmpeg8)
+    make_torchcodec_libraries(7 torchcodec::ffmpeg7)
+    make_torchcodec_libraries(6 torchcodec::ffmpeg6)
+    make_torchcodec_libraries(4 torchcodec::ffmpeg4)
+    make_torchcodec_libraries(5 torchcodec::ffmpeg5)
 else()
     message(
         STATUS

src/torchcodec/_core/__init__.py

@@ -30,6 +30,7 @@
     encode_video_to_file,
     encode_video_to_file_like,
     encode_video_to_tensor,
+    ffmpeg_major_version,
     get_ffmpeg_library_versions,
     get_frame_at_index,
     get_frame_at_pts,
@@ -42,5 +43,4 @@
     get_next_frame,
     scan_all_streams_to_update_metadata,
     seek_to_pts,
-    variant,
 )

src/torchcodec/_core/fetch_and_expose_non_gpl_ffmpeg_libs.cmake

@@ -21,8 +21,6 @@ set(
 )
 
 if (LINUX)
-    set(lib_dir "lib")
-
     set(
         platform_url
         ${base_url}/linux_x86_64
@@ -48,58 +46,7 @@ if (LINUX)
         f8_sha256
         c55b3c1a4b5e4d5fdd7c632bea3ab6f45b4e37cc8e0999dda3f84a8ed8defad8
     )
-    set(
-       f4_library_file_names
-       libavutil.so.56
-       libavcodec.so.58
-       libavformat.so.58
-       libavdevice.so.58
-       libavfilter.so.7
-       libswscale.so.5
-       libswresample.so.3
-    )
-    set(
-       f5_library_file_names
-       libavutil.so.57
-       libavcodec.so.59
-       libavformat.so.59
-       libavdevice.so.59
-       libavfilter.so.8
-       libswscale.so.6
-       libswresample.so.4
-    )
-    set(
-       f6_library_file_names
-       libavutil.so.58
-       libavcodec.so.60
-       libavformat.so.60
-       libavdevice.so.60
-       libavfilter.so.9
-       libswscale.so.7
-       libswresample.so.4
-    )
-    set(
-       f7_library_file_names
-       libavutil.so.59
-       libavcodec.so.61
-       libavformat.so.61
-       libavdevice.so.61
-       libavfilter.so.10
-       libswscale.so.8
-       libswresample.so.5
-    )
-    set(
-       f8_library_file_names
-       libavutil.so.60
-       libavcodec.so.62
-       libavformat.so.62
-       libavdevice.so.62
-       libavfilter.so.11
-       libswscale.so.9
-       libswresample.so.6
-    )
 elseif (APPLE)
-    set(lib_dir "lib")
     set(
         platform_url
         ${base_url}/macos_arm64
@@ -124,60 +71,7 @@ elseif (APPLE)
         f8_sha256
         beb936b76f25d2621228a12cdb67c9ae3d1eff7aa713ef8d1167ebf0c25bd5ec
     )
-
-    set(
-       f4_library_file_names
-       libavutil.56.dylib
-       libavcodec.58.dylib
-       libavformat.58.dylib
-       libavdevice.58.dylib
-       libavfilter.7.dylib
-       libswscale.5.dylib
-       libswresample.3.dylib
-    )
-    set(
-       f5_library_file_names
-       libavutil.57.dylib
-       libavcodec.59.dylib
-       libavformat.59.dylib
-       libavdevice.59.dylib
-       libavfilter.8.dylib
-       libswscale.6.dylib
-       libswresample.4.dylib
-    )
-    set(
-       f6_library_file_names
-       libavutil.58.dylib
-       libavcodec.60.dylib
-       libavformat.60.dylib
-       libavdevice.60.dylib
-       libavfilter.9.dylib
-       libswscale.7.dylib
-       libswresample.4.dylib
-    )
-    set(
-       f7_library_file_names
-       libavutil.59.dylib
-       libavcodec.61.dylib
-       libavformat.61.dylib
-       libavdevice.61.dylib
-       libavfilter.10.dylib
-       libswscale.8.dylib
-       libswresample.5.dylib
-    )
-    set(
-       f8_library_file_names
-       libavutil.60.dylib
-       libavcodec.62.dylib
-       libavformat.62.dylib
-       libavdevice.62.dylib
-       libavfilter.11.dylib
-       libswscale.9.dylib
-       libswresample.6.dylib
-    )
-
 elseif (WIN32)
-    set(lib_dir "bin")
     set(
         platform_url
         ${base_url}/windows_x86_64
@@ -202,57 +96,6 @@ elseif (WIN32)
         f8_sha256
         bac845ac79876b104959cb0e7b9dec772a261116344dd17d2f97e7ddfac4a73f
     )
-
-    set(
-        f4_library_file_names
-        avutil.lib
-        avcodec.lib
-        avformat.lib
-        avdevice.lib
-        avfilter.lib
-        swscale.lib
-        swresample.lib
-    )
-    set(
-        f5_library_file_names
-        avutil.lib
-        avcodec.lib
-        avformat.lib
-        avdevice.lib
-        avfilter.lib
-        swscale.lib
-        swresample.lib
-    )
-    set(
-        f6_library_file_names
-        avutil.lib
-        avcodec.lib
-        avformat.lib
-        avdevice.lib
-        avfilter.lib
-        swscale.lib
-        swresample.lib
-    )
-    set(
-        f7_library_file_names
-        avutil.lib
-        avcodec.lib
-        avformat.lib
-        avdevice.lib
-        avfilter.lib
-        swscale.lib
-        swresample.lib
-    )
-    set(
-        f8_library_file_names
-        avutil.lib
-        avcodec.lib
-        avformat.lib
-        avdevice.lib
-        avfilter.lib
-        swscale.lib
-        swresample.lib
-    )
 else()
     message(
         FATAL_ERROR
@@ -293,68 +136,11 @@ FetchContent_Declare(
 
 FetchContent_MakeAvailable(f4 f5 f6 f7 f8)
 
-add_library(ffmpeg4 INTERFACE)
-add_library(ffmpeg5 INTERFACE)
-add_library(ffmpeg6 INTERFACE)
-add_library(ffmpeg7 INTERFACE)
-add_library(ffmpeg8 INTERFACE)
+include("${CMAKE_CURRENT_SOURCE_DIR}/../share/cmake/TorchCodec/ffmpeg_versions.cmake")
 
 # Note: the f?_SOURCE_DIR variables were set by FetchContent_MakeAvailable
-target_include_directories(ffmpeg4 INTERFACE ${f4_SOURCE_DIR}/include)
-target_include_directories(ffmpeg5 INTERFACE ${f5_SOURCE_DIR}/include)
-target_include_directories(ffmpeg6 INTERFACE ${f6_SOURCE_DIR}/include)
-target_include_directories(ffmpeg7 INTERFACE ${f7_SOURCE_DIR}/include)
-target_include_directories(ffmpeg8 INTERFACE ${f8_SOURCE_DIR}/include)
-
-
-list(
-    TRANSFORM f4_library_file_names
-    PREPEND ${f4_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f4_library_paths
-)
-list(
-    TRANSFORM f5_library_file_names
-    PREPEND ${f5_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f5_library_paths
-)
-list(
-    TRANSFORM f6_library_file_names
-    PREPEND ${f6_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f6_library_paths
-)
-list(
-    TRANSFORM f7_library_file_names
-    PREPEND ${f7_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f7_library_paths
-)
-list(
-    TRANSFORM f8_library_file_names
-    PREPEND ${f8_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f8_library_paths
-)
-
-target_link_libraries(
-    ffmpeg4
-    INTERFACE
-    ${f4_library_paths}
-)
-target_link_libraries(
-    ffmpeg5
-    INTERFACE
-    ${f5_library_paths}
-)
-target_link_libraries(
-    ffmpeg6
-    INTERFACE
-    ${f6_library_paths}
-)
-target_link_libraries(
-    ffmpeg7
-    INTERFACE
-    ${f7_library_paths}
-)
-target_link_libraries(
-    ffmpeg8
-    INTERFACE
-    ${f8_library_paths}
-)
+add_ffmpeg_target(4 "${f4_SOURCE_DIR}")
+add_ffmpeg_target(5 "${f5_SOURCE_DIR}")
+add_ffmpeg_target(6 "${f6_SOURCE_DIR}")
+add_ffmpeg_target(7 "${f7_SOURCE_DIR}")
+add_ffmpeg_target(8 "${f8_SOURCE_DIR}")

src/torchcodec/_core/ops.py

@@ -6,7 +6,6 @@
 
 import io
 import json
-import os
 import warnings
 from types import ModuleType
 from typing import List, Optional, Tuple, Union
@@ -22,8 +21,6 @@
 
 _pybind_ops: Optional[ModuleType] = None
 
-variant = None
-core_library_path = None
 
 def load_torchcodec_shared_libraries():
     # Successively try to load the shared libraries for each version of FFmpeg
@@ -59,11 +56,7 @@ def load_torchcodec_shared_libraries():
             _pybind_ops = _load_pybind11_module(
                 pybind_ops_module_name, pybind_ops_library_path
             )
-            global variant
-            global core_library_path
-            variant = ffmpeg_major_version
-            core_library_path = decoder_library_path
-            return
+            return ffmpeg_major_version, decoder_library_path
         except Exception as e:
             # TODO: recording and reporting exceptions this way is OK for now as  it's just for debugging,
             # but we should probably handle that via a proper logging mechanism.
@@ -89,7 +82,12 @@ def load_torchcodec_shared_libraries():
     )
 
 
-load_torchcodec_shared_libraries()
+# These are definitions of variables exposed as TorchCodec APIs:
+# * `ffmpeg_major_version` is a major version of FFmpeg against which the loaded
+#    TorchCodec dynamic libraries were built.
+# * `core_library_path` is a full path (including library name) to the loaded
+#   TorchCodec core library.
+ffmpeg_major_version, core_library_path = load_torchcodec_shared_libraries()
 
 
 # Note: We use disallow_in_graph because PyTorch does constant propagation of